1. Field of the Invention
The present invention relates to a blower for vehicles, and more particularly, to a blower for vehicles, which includes guide walls formed on a bypass passageway formed between a scroll case and an outer case to send the indoor air and the outdoor air to a lower suction opening of the scroll case, thereby reducing suction noise by guiding an uniform flow of air introduced into the lower suction opening, preventing deformation of the outer case, and preventing a droop of the air filter by supporting a lower portion of an air filter when an intake duct injection-molded in a vertically parted mold is applied thereto.
2. Background Art
In general, an air conditioner 1 for a vehicle is a device which is adapted to allow indoor air and outdoor air of the vehicle to be introduced thereto, heat or cool the introduced air, and send the heated or cooled air to the inside of the vehicle to thereby cool or heat the inside of the vehicle. As shown in FIG. 1, the air conditioner includes: a blower 10 having an indoor air inlet 21 and an outdoor air inlet 22 formed on the upper portion thereof, an intake door 23 for selectively opening and closing the indoor air inlet 21 and the outdoor air inlet 22, and a blower fan 31 for forcedly sending the indoor air and the outdoor air toward an inlet 43 of an air-conditioning case 40; and the air-conditioning case 40 having the inlet 43 for introducing the air blown from the blower 10 thereto and an outlet 44 for discharging the air, wherein an evaporator 41 and a heater core 42 are mounted in the air-conditioning case 40 in order in a state where they are spaced apart from each other at a predetermined interval.
Here, the intake door 23 adopts one of various types, for instance, a flat type, a dome-type, to which air pressure is applied a little, a cylindrical type, a hemispherical type, and so on.
FIG. 2 is a cross-sectional view of a blower for vehicles, to which a typical unidirectional suction type blower fan is applied. As shown in FIG. 2, the blower 10 includes: a scroll case 30 having a discharge port 35 formed on a side thereof and connected to an air-conditioning case 40, the scroll case 30 being opened at an upper portion thereof; an intake duct 20 mounted on the upper portion of the scroll case 30, the intake duct 20 having an indoor air inlet 21 and an outdoor air inlet 22 for respectively introducing the indoor air and the outdoor air and an intake door 23 for selectively opening and closing the indoor air inlet 21 and the outdoor air inlet 22; a suction opening 37 adapted to provide an air suction passageway between the intake duct 20 and the scroll case 30; a blower fan 31 rotatably mounted on the scroll case 30; and a motor 39 mounted below the scroll case 30 to rotate the blower fan 31 and connected with the blower fan 31. In FIG. 2, the reference numeral 38 designates an air filter 38 for filtering foreign matters contained in the air sucked to the intake duct 20, and the air filter 38 can be mounted selectively.
In addition, the intake door 23 is actuated by a cable (not shown) and an actuator (not shown), which are mounted separately.
Furthermore, the blower fan 31 adopts a unidirectional suction type structure, and hence, sucks air from one axial direction, namely, from the suction opening 37 and discharges it in a radial direction according to the rotation thereof. The blower fan 31 includes a hub plate 32 connected to a shaft of the motor 39, a plurality of blades 33 radially arranged along the edge of an upper face of the hub plate 32, and a support ring 34 for connecting and supporting upper ends of the blades 33 with one another.
Moreover, the hub plate 32 is generally concaved toward the inside (namely, upper portion) of a space formed by the blades 33, and thereby, the motor 39 is connected to the hub plate 32 in a state where a portion of the motor 39 is inserted into the space.
Accordingly, when the blower fan 31 is rotated by driving of the motor 39, the indoor air or the outdoor air is introduced through the suction opening 37 in the axial direction of the blower fan 31 after passing through the indoor air inlet 21 or the outdoor air inlet 22, which is selectively opened according to a control of an opening level of the intake door 23, flows along an inclined upper face of the hub plate 32, and then, is discharged in the radial direction of the blower fan 31. The air is blown to the inside of the air-conditioning case 40 through the discharge port 35 in a state where the air is gradually increased in pressure and volume while flowing along a side wall of the scroll case 30.
However, the blower 10, to which the unidirectional suction type blower fan 31 is applied, has a problem in that an air flow distribution is not uniform in the upper and lower parts of the blower 10 since the air is mainly discharged along an inclined surface of the hub plate 31 as shown in FIG. 2 when the air is discharged from the blower fan 31 in the radial direction.
In addition, referring to FIG. 3, an air flow structure formed at a cut-off area 36 where a scroll portion 30a and the discharge port 35 of the scroll case 30 meet with each other will be described. At the cut-off area 36, the air directly flowing toward the discharge port 35 after being discharged from the blower fan 31 in the radial direction collides against and is mixed with the air flowing toward the discharge port 35 along the side wall of the scroll portion 30a after being discharged from the blower fan 31 in the radial direction to thereby generate a turbulent flow. As described above, when the air flow distribution is not uniform and the turbulent flow is generated, an air volume is reduced and noise is generated greatly.
In order to solve the problems of the typical blower 10, to which the unidirectional suction type blower fan 31 is applied, a bidirectional suction type blower for sucking and discharging air bidirectionally has been proposed to increase the air volume, reduce noise, and perform a two-layer air flow.
Japanese Utility Model Laid-open Publication No. Hei 5-10016 discloses an example of the bidirectional suction type blower. As shown in FIG. 4, the bidirectional suction type blower includes: a scroll case 30 having upper and lower suction openings 37a and 37b formed at upper and lower face thereof and a discharge port (not shown) formed on a side thereof; a bidirectional suction type blower fan 31 rotatably mounted on the scroll case 30 and having a plurality of blades 33a and 33b integrally formed on upper and lower portions of a hub plate 32 and opposed to each other; an outer case 50 mounted on the outer surface of the scroll case 30 and having a bypass passageway 51 formed between the outer case 50 and the scroll case 30 for sending air toward the lower suction opening 37b; an intake duct 20 formed on an upper end of the outer case 50 for sending air toward the upper and lower suction openings 37a and 37b, the intake duct 20 having an outdoor air inlet 22 and a plurality of indoor air inlets 21 formed on an upper portion thereof and an intake door 23 mounted therein for opening and closing the indoor air inlets 21 and the outdoor air inlet 22; and a motor 39 connected to the hub plate 32 through the lower suction opening 37b to rotate the bidirectional suction type blower fan 31.
In the meantime, on a lower portion of the outer case 50 mounted are a plurality of indoor air inlets 21 and a door 23a for opening and closing the indoor air inlets 21.
According to the blower shown in FIG. 4, in an outdoor air inflow mode, in a state where all indoor air inlets 21 are closed but only the outdoor air inlet 22 is opened, the outdoor air is distributably sucked toward the upper and lower suction openings 37a and 37b. Furthermore, in an indoor air inflow mode, in a state where the outdoor air inlet 22 is closed but all of the indoor air inlets 21 are opened, the indoor air is distributedly sucked toward the upper and lower suction openings 37a and 37b. Additionally, in an indoor and outdoor air inflow mode, in a state where the outdoor air inlet 22 is partially opened and some of the indoor air inlets 21 are selectively opened, the indoor air and the outdoor air are mixed with each other and sucked toward the upper suction opening 37a and the indoor air is sucked toward the lower suction opening 37b. 
In the blower, some of the air introduced through the indoor and outdoor air inlets 21 and 29 of the intake duct 20 is sucked toward the lower suction opening 37b through the bypass passageway 51, and in this instance, noise is generated since a flow of the air sucked toward the lower suction opening 37b through the bypass passageway 51 is not uniform.
Furthermore, since the outer case 50 is separated apart outwardly from the scroll case 30 at a predetermined interval by the bypass passageway 51, the outer case 50 is transformed.
Meanwhile, if the air filter 38 is mounted between the outer case 50 and the intake duct 20, a horizontal support structure (38a in FIG. 2) is formed on a bottom face of the intake duct 20 to support a lower portion of the air filter 38. In this instance, the air filter support structure 38a can be formed on the intake duct 20, which is injection-molded in a horizontally parted mold, but not be formed on an intake duct, which is injection-molded in a vertically parted mold. i.e., in a mold having horizontal parting line, due to a feature of the mold. Accordingly, even though the intake duct 20 injection-molded in the horizontally parted mold may generate leak and noise due to ununiformity of a sealed portion at the parting line portion, the horizontally parted mold must be used since it can mold the support structure 38a for the lower portion of the air filter.
Of course, if the intake duct is injection-molded in the vertically parted mold, since the support structure 38a for the lower portion of the air filter cannot be molded, the lower portion of the air filter 38 droops.